In this study, non-destructive technologies that can be applied to evaluate the integrity of valve materials, safety against internal pressure caused by corrosion, and the blocking function of large-diameter water valves during operation without requiring specimen collection or manpower entering the inside of the valve were tested to assess the reliability of the technologies and their suitability for field application. The results showed that the condition of the graphite structure inside the valve body can be evaluated directly through the optical microscope in the field without specimen collection for large-diameter water butterfly valves, and the depth of corrosion inside the valve body can be determined by array ultrasound and the tensile strength can be measured by instrumented indentation test. The reliability of each of these non-destructive techniques is high, and they can be widely used to evaluate the condition of steel or cast iron pipes that are significantly smaller in thickness than valves. Evaluation of blocking function of the valves with mixed gas showed that it can be detected even when a very low flow rate of mixed gas passes through the disk along with the water flow. Finally, as a result of evaluating the field applicability of non-destructive technologies for three old butterfly valves installed in the US industrial water pipeline, it was found that it is possible to check the material and determine the suitability of large-diameter water valves without taking samples, and to determine the corrosion state and mechanical strength. In addition, it was possible to evaluate safety through the measurement results, and it is judged that the evaluation of the blocking function using mixed gas will help strengthen preventive response in the event of an accident.

강풍, 폭우 등 이상기후의 대형화와 빈도 증가로 인해 나무가 부러지거나 쓰러지는 훼손이 증가하고 있으나 나무 내부의 공동, 부후 등 구조적 결함은 육안조사로 판별이 어렵기 때문에 예측을 통한 사전대응에 한계가 있다. 비파괴 음파단층촬영은 나무에 미치는 물리적 훼손을 최소화하면서 내부결함을 추정하는 방법으로 내부결함 진단에 효율적이 나 수종별 정확도에 차이가 발생하기 때문에 현장적용 전 측정결과의 신뢰성 분석이 선행되어야 한다. 이번 연구는 우리나라 대표 수종인 소나무와 은행나무 노거수를 대상으로 음파단층촬영의 신뢰성 검증을 위해 침입성 드릴저항 측정을 교차 적용하여 목재 내부결함을 측정하고 평가결과를 비교하였다. 두 집단 간 결함부 측정 평균값에 대한 t검정 결과 소나무는 통계적으로 유의한 차이가 없는 반면, 은행나무는 유의성에 차이가 있었다. 선형회귀분석 결과 두 수종 모두 드릴저항그래프의 결함이 증가할 때 음파단층영상 결함이 증가하는 양의 상관관계를 보였다.

PURPOSES : The exposed aggregate number (EAN) and mean texture depth (MTD) of exposed aggregate concrete pavement (EACP) influence the functional performance of EACP in terms of pavement noise and skid resistance. The selection of the exposure time of EACP is important because the designed EAN and MTD of EACP can be achieved when the exposure process is performed at an appropriate time. On the one hand, too early exposure may cause protrusions and unwanted removal of aggregates and mortar. On the other hand, late exposure may cause difficulty in exposure of the mortar. In this study, a method to determine the optimum exposure time for EACP is suggested using a non-destructive method. METHODS : A set of laboratory tests was performed to investigate the variation in EAN and MTD of EACP according to the elastic modulus obtained by non-destructive equipment. From the results of this investigation, the optimum exposure time using the non-destructive method and the exposure time window (ETW) method was suggested. In addition, the usefulness of ETW suggested by laboratory tests was verified from a field application. RESULTS : From the laboratory tests, it was found that the targets of the surface condition of EACP (EAN: 59 per 25 cm2, MTD: 1.39 mm) can be achieved when the concrete elastic modulus is higher than 20GPa. The proposed guideline using the non-destructive method was applied for the field construction of EACP and achieved similar results. CONCLUSIONS : It was found that the proposed guideline for determining the exposure time window based on non-destructive testing is useful.

PURPOSES: Spalling is one of the primary problems that lead to the damage of concrete pavements. The purpose of the study is to analyze the impact range of spalling that occurred in an area of concrete pavement by applying a variety of nondestructive and destructive testing methods. METHODS: Spalling of the concrete pavement was categorized into four different sizes, 0 cm, 7.5 cm, 15 cm, and 30 cm. Nondestructive and destructive tests were performed at the point of spalling and 1 m away, respectively, and the obtained results were compared. The nondestructive tests included the electrical resistance test and the ultrasonic velocity test as well as strength tests by Schmidt hammer and concrete tester. The destructive tests included the direct compressive strength test and the chloride content test using field cored specimens. The test results helped in the analysis of the correlation between the current spalling damage condition and the expected damage acceleration. RESULTS: Based on the present study, the repair area and depth of spalling for a partial depth repair was suggested. It was also shown that the size of the spalling is highly correlated with the chloride content and the electrical resistance of the concrete pavement. CONCLUSIONS: The degree of spalling deterioration was found to be highly correlated with the chloride content and electrical resistance of the concrete pavement and based on the results, the extent of repair could be determined more quantitatively.

PURPOSES: This study is to estimate nondestructive strength equation based on probability for bridges using field test data. METHODS: In this study, a series of the field inspection and the test have been performed on 297 existing bridges, in order to evaluate the bridges, based on the test results of the in-depth inspection, and the estimated strengths by means of the nondestructive strength equations are analyzed and compared with results of the core specimen strengths. RESULTS: According to results of analyses, In case of standard design compressive strength of concrete is 18MPa, 21MPa, similar reliability of RILEM equation were 0.89~0.90, but in case of standard design compressive strength of concrete is 35MPa, 40MPa were 0.4~0.56. According to standard design compressive strength of concrete is 40MPa, similar reliability of ultrasonic pulse velocity method equation were 0.56. CONCLUSIONS: RILEM equation had high similar reliability than other equation in case of standard design compressive strength of concrete is 18MPa, 21MPa, but had low similar reliability than other equation in case of standard design compressive strength of concrete is 35MPa, 40MPa. and ultrasonic pulse velocity method equation had low similar reliability than other equation in case of standard design compressive strength of concrete is 40MPa.

Plant physiological indices for Euryale ferox Salisb. an endangered aquatic plant from Gyeongsan Province, were analyzed in this study. The NDVI (Normalized Difference Vegetation Index) was highest at 0.820 in Dongguji and lowest at 0.592 in Dongjaji; the SR (Simple Ratio) index was highest at 10.240 in Dongguji and lowest at 4.312 in Dongjaji; and the PRI (Photochemical Reflectance Index) was highest at 0.039 in Dongguji and lowest at −0.036 in Dongjaji. The CRI1 (Carotenoid Reflectance Index 1) index was in Sahwaji and Waji at 8.881 and 12.988, respectively, and the CRI2 (Carotenoid Reflectance Index 2) index was highest at 7.889 in Sahwaji and lowest at 11.889 in Dongjaji.

PURPOSES : This paper presents a comparison study between dynamic and static analyses of falling weight deflectometer (FWD) testing, which is a test used for evaluating layered material stiffness. METHODS: In this study, a forward model, based on nonlinear subgrade models, was developed via finite element analysis using ABAQUS. The subgrade material coefficients from granular and fine-grained soils were used to represent strong and weak subgrade stiffnesses, respectively. Furthermore, the nonlinearity in the analysis of multi-load FWD deflection measured from intact PCC slab was investigated using the deflection data obtained in this study. This pavement has a 14-inch-thick PCC slab over finegrained soil. RESULTS: From case studies related to the nonlinearity of FWD analysis measured from intact PCC slab, a nonlinear subgrade modelbased comparison study between the static and dynamic analyses of nondestructive FWD tests was shown to be effectively performed; this was achieved by investigating the primary difference in pavement responses between the static and dynamic analyses as based on the nonlinearity of soil model as well as the multi-load FWD deflection. CONCLUSIONS : In conclusion, a comparison between dynamic and static FEM analyses was conducted, as based on the FEM analysis performed on various pavement structures, in order to investigate the significance of the differences in pavement responses between the static and dynamic analyses.

Thermographic imaging based non-destructive evaluation proceeds measuring the defect or internal condition of civil structures. To demonstrate the feasibility of the method, the infrared camera system is applied to various specimens. The technique described in this paper may allow us to find their numbers, locations, and the extent of damaged steels from the measurement in the long distance. In addition, a reinforced concrete specimens with different penetration depths is tested using the active thermography method, and to study the influence on the detecting internal rebar in cooled and heated conditions. The experimental results demonstrate that thermographic imaging method is useful for detecting the damage of steel structures and the unknown rebar in the concrete.

The purpose of this paper is to find an limitation to detect the defect of damaged asphalt pavement structures for infrared thermography. We use heat source of a natural light to detect the defect efficiently. The heat source was applied to the asphalt specimens. Four asphalt specimens were used: one was the asphalt containing depth of 1cm internal timber, two was the asphalt containing depth of 2cm internal void, Three was the asphalt containing depth of 3cm internal timber and four was not the asphalt containing internal timber. It was found that the depth of 3cm internal timber could be detected by this method. In addition, we used the image processing to make the damage zone displayed clear in the image obtained from the thermographic operation.

The study is conducted in order to establish validity of industrial safety field's neo-qualification composition by suggesting reengineering procedure of NCS based industrial safety field's qualifying occupational plan. The study is conducted in order to establish validity of industrial safety field's neo-qualification composition by suggesting reengineering procedure of NCS based industrial safety field's qualifying occupational plan. NCS based neo-qualification plan is deveopled into progress as following steps; First, planning NCS neo-qualification system. Second, presenting work·education combined program certification standard. Third, developing NCS based neo-qualification assessment standard. Fourth, developing work·education qualification prototype problem. The process of qualification plan was composed with Worksheet 14 and with 4phase being completing summary of each section, certification and development of assessment standard, and development of prototype problem. As a result, Industrial safety manager was redesigned into Industrial sfety manager and Construction Safety Manager, and Occupational Health Care Manager was redesigned into Occupational Health Care Manager and Industrial Health Manager. This study, in conclusion, suggests development of qualifying occupation that could be applied to the integrated management system and development of future industrial safety field's specialized neo-qualifying occupation.